This invention relates in general to the construction of building structures, and in particular to a fastener for attaching frame members of a patio enclosure.
Patio enclosures are typically constructed with a plurality of elongated beams or frame members which are fastened to one another to form a framework. The framework generally provides the structural integrity and shape of the patio enclosure. Panels, screens, windows, and doors are commonly inserted between various frame members to form an enclosed structure. The frame members can be oriented vertically, horizontally, or angled with respect to one another. Additionally, a roof structure can be installed over the patio enclosure.
The frame members are relatively narrow compared to their length. Frame members have been constructed out of many types of materials, such as wood, aluminum, and polymeric materials, such as vinyl. In recent times, frame members have been formed from multiple materials to form a composite frame member. A composite frame member generally has an inner core covered by an outer casing. The outer casing is made of a different material than the inner core. For example, the inner core can be a relatively rigid material, such as wood or aluminum, which provides rigidity and the structural integrity for the frame member. The outer casing or skin can be made of a suitable material having weather resistant properties and which is aesthetically pleasing, such as vinyl or other suitable polymeric materials. If vinyl or other polymeric materials are used for the outer casing, the outer casing can be manufactured using an extrusion process, and is preferably formed with a hollow interior. The inner core is inserted into the hollow interior of the outer casing to form a frame member having a relatively rigid structure and having exceptional wear properties for withstanding an outdoor environment.
Frame members are supplied in various cross-sectional shapes depending on their application and location in the patio enclosure. Commonly, the cross-sectional shape of frame members is generally square or rectangular. The frame members can include pairs of elongated relatively thin planar ribs extending along the length of one or more sides of the frame member. Typically, the ribs extend normal to a flat surface defined by the side of the frame member. The ribs form a track in which panels or widows can be inserted therebetween to secure the panel or window to the frame member. The ribs of adjacent frame members are dimensioned and oriented so that they are in alignment with each other and are generally coplanar to form a continuous track surrounding the periphery of the panel or window. If the frame member is formed by an extrusion process, the ribs can easily be formed integrally with the extruded outer casing.
Generally, the frame members are positioned and fastened together such that an end of one frame member abuts a side of another frame member. The frame members are commonly at right angles with respect to one another and form what is known in the art as a butt joint. It is known to fasten frame members by conventional angle brackets having a pair of relatively flat legs perpendicular to one another. The legs of the bracket are fastened to the adjacent sides of the adjoining frame members, such as by self-tapping screws.
It is also known to use an insert to assist in fastening frame members together. There is illustrated in FIG. 1, a joint, indicated generally at 100, for use in a conventional known prior art patio enclosure. The joint 100 is formed by joining a first frame member 102 to a second frame member 104 with the aid of an insert 106. The frame members 102 and 104 are similar in structure. The frame members 102 and 104 are composite frame members having a polymeric outer casing 108 and a rigid inner core 110. The frame members 102 and 104 include outwardly extending ribs 112 to form tracks for retaining doors, windows, and panels of the patio enclosure. The insert 106 is generally U-shaped having a pair of spaced apart parallel legs 114 joined by a web 116. The insert 106 and the inner cores 110 of the frame members 102 and 104 are formed of aluminum, a relatively rigid material.
To form the joint 100, the web 116 of the insert 106 is fastened to a side surface 118 of the frame member 102 by a threaded fastener (not shown). The legs 114 of the insert 106 are then inserted into a bore 120 of the inner core 110 of the frame member 104. The legs 114 of the insert 106 are then fastened to the side of the frame member 104 by threaded fasteners threaded through a side wall 121 of the frame member 104.
To form a relatively secure joint, a structural end of the frame member 104 should be in abutment with the structural side of the frame member 102. Since the outwardly extending ribs 112 of the frame members 102 and 104 are oriented so that they align with each other, the end of the frame member 104 will not abut the flat side surface 118 of the mating frame member 102 due to the interference from the ribs 112. In other words, the end of the frame member 104 will abut the outer edges of the ribs 112 of the frame member 104. Fastening the frame members 102 and 104 at this displacement position is undesirable because of the formation of a relatively weak joint due to the lack of direct contact of the structural members. To overcome this problem, portions of the frame members, such as the ribs 112, from one or both of the frame members 102 and 104 are removed or cut out to form notches. For example, as shown in FIG. 1, notches 122 are formed in the ribs 112 of the frame member 104. The length of the notch 122 corresponds to the width of the rib 112 extending from the side surface 118. The notch 122 provides clearance for the ribs 112 of the end of the frame member 104 from interfering with the ribs 112 of the frame member 102 when the end of the frame member 104 is positioned adjacent the side surface 118 of the frame member 102. A generally rectangular notch 124 is formed in the side surface 118 of the frame member 102 corresponding to the dimensions of the web 116 of the insert 106. The notch 124 allows direct contact between the web 116 of the insert 106 and the inner core 110 of the frame member 103. Since the surface area of the web 116 is relatively small, the insert 106 is mounted directly to the surface of the inner core 110.
The appropriate portions (notches) of the frame members can be removed manually by hand tools or by power tools, such as routers or milling machines. Special cutting tools have been developed to cut an appropriate notch into the frame members. However, these cutting tools can be relatively expensive, especially if different configurations of notches must be machined corresponding to frame members having different cross-sections.
Although the removal of the portions of the frame members overcomes the problem of joining the structural portions of the frame members to form a butt joint, it is very time consuming and intricate. Commonly, the frame members are provided in relatively long lengths, such as 20 feet in length, and are cut to the appropriate size at the job site where the patio enclosure is being built. If the frame members are sized at the job site, the appropriate tools must be available to remove the appropriate portions of the frame embers to accommodate the butt joint. To avoid having the workers on the job site cutting the appropriate notches, it is known to cut the frame members at a manufacturing facility prior to assembly at the job site. However, any complications, such as inaccurate measurements or inventory errors, will complicate assembly of the patio enclosure because of non-mating frame members. Often, the workers must notch the frame members using hand tools regardless of having the premeasured and notched frame members.